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David K Stevenson

Publications and source records attributed to David K Stevenson.

At least 55 records · Page 3Linked to original sources
PubMed2004

Parenteral glutamine supplementation does not reduce the risk of mortality or late-onset sepsis in extremely low birth weight infants.

BACKGROUND: Glutamine is one of the most abundant amino acids in both plasma and human milk, yet it is not included in standard intravenous amino acid solutions. Previous studies have suggested that parenteral nutrition (PN) supplemented with glutamine may reduce sepsis and mortality in critically ill adults. Whether glutamine supplementation would provide a similar benefit to extremely low birth weight (ELBW) infants is not known. METHODS: We performed a multicenter, randomized, double-masked, clinical trial to assess the safety and efficacy of early PN supplemented with glutamine in decreasing the risk of death or late-onset sepsis in ELBW infants. Infants 401 to 1000 g were randomized within 72 hours of birth to receive either TrophAmine (control) or an isonitrogenous study amino acid solution with 20% glutamine whenever they received PN up to 120 days of age, death, or discharge from the hospital. The primary outcome was death or late-onset sepsis. RESULTS: Of the 721 infants who were assigned to glutamine supplementation, 370 (51%) died or developed late-onset sepsis, as compared with 343 of the 712 infants (48%) assigned to control (relative risk: 1.07; 95% confidence interval: 0.97-1.17). Glutamine had no effect on tolerance of enteral feeds, necrotizing enterocolitis, or growth. No significant adverse events were observed with glutamine supplementation. CONCLUSIONS: Parenteral glutamine supplementation as studied did not decrease mortality or the incidence of late-onset sepsis in ELBW infants. Consequently, although no harm was demonstrated, routine use of parenteral glutamine supplementation cannot be recommended in this population.

Dietary Supplements↗
PubMed2004

Transcutaneous bilirubin measurements and serum total bilirubin levels in indigenous African infants.

OBJECTIVE: The objective of this study was to determine whether transcutaneous bilirubin (TcB) measurements correlate with serum total bilirubin (STB) levels in indigenous, darkly pigmented African newborns with varying degrees of skin pigmentation, some of which had developed kernicterus. METHODS: Jaundiced infants who were < or =2 weeks of age and admitted to Baptist Medical Center-Eku (Eku; n = 29) and Jos University Teaching Hospital (Jos; n = 98) in Nigeria were studied. TcB measurements using the BiliChek were made simultaneously with blood sampling for STB measurements by spectrophotometry before phototherapy. RESULTS: Using linear regression analysis, we found that measurements of TcB correlated well with those of STB with r values of.90 and.88 for Eku and Jos, respectively. Mean bias and imprecision of TcB measurements as compared with STB measurements for the total population was 0.5 +/- 7.6 mg/dL using the method of Bland and Altman. At STB > or 12 mg/dL, correlation (r =.84) and bias and imprecision (-1.2 +/- 8.6 mg/dL) of measurements were only slightly poorer. Furthermore, when infants were grouped by degree of skin pigmentation, correlations of TcB and STB measurements remained strong. CONCLUSIONS: From these results, we can conclude that TcB measurements are a useful and reliable index for estimating STB levels in pigmented neonates, including those with hyperbilirubinemia and kernicterus. In the absence of reliable STB measurements, the relatively simple and noninvasive TcB measurements can be an important adjunct in directing phototherapy and exchange transfusions, thereby preventing bilirubin-induced morbidity and mortality in low-technology clinical environments.

Bias↗
PubMed2004

Hyperbilirubinemia among African American, glucose-6-phosphate dehydrogenase-deficient neonates.

BACKGROUND: Although glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is prevalent in African Americans, their risk of associated neonatal hyperbilirubinemia has not been prospectively studied. OBJECTIVE: To compare hemolysis and the risk of hyperbilirubinemia among African American, G-6-PD-deficient neonates (study group) and G-6-PD-normal control subjects. METHODS: Consecutive, healthy, term and near-term, male neonates born to African American mothers comprised the patient cohort. G-6-PD testing was performed with umbilical cord blood samples. Routine management included measurement of the end tidal carbon monoxide level corrected for ambient carbon monoxide level (ETCOc) within 4 hours after delivery (assessment of hemolysis), > or =1 predischarge bilirubin determination, and additional bilirubin testing as clinically indicated. Indications for phototherapy were identical for study patients and control subjects. Neonates were monitored for the first 1 week of life. ETCOc results, the incidence of hyperbilirubinemia (defined as a transcutaneous or plasma total bilirubin concentration of > or =95th percentile for the hour of life), and the need for phototherapy were compared between the G-6-PD-deficient and G-6-PD-normal groups. RESULTS: Five hundred male patients were enrolled, of whom 64 (12.8%) were G-6-PD-deficient. ETCOc values (median and interquartile range) were higher among G-6-PD-deficient neonates than among control neonates (2.4 ppm [2.0-2.9 ppm] vs 2.1 ppm [1.7-2.5 ppm]). More G-6-PD-deficient neonates developed hyperbilirubinemia than did control subjects (14 of 64, 21.9%, vs 29 of 436, 6.7%; relative risk: 3.27; 95% confidence interval: 1.83-5.86), whereas 13 (20.3%) met the criteria for phototherapy, compared with 25 control subjects (5.7%) (relative risk: 3.53; 95% confidence interval: 1.91-6.56). No cases of kernicterus were observed. CONCLUSIONS: Within the African American neonatal population, there is a subgroup of G-6-PD-deficient infants with elevated rates of hemolysis, a higher incidence of hyperbilirubinemia, and a greater requirement for phototherapy, compared with G-6-PD-normal control subjects. These newborns should be monitored vigilantly for the development of hyperbilirubinemia.

Bilirubin↗
PubMed2003

Gestational pattern of heme oxygenase expression in the rat.

Fetal growth is influenced by many intrinsic and extrinsic factors. Our objective was to determine the pattern of heme oxygenase (HO) expression in the pregnant rat and to study its association with fetal growth and growth factors. Uterine tissues were obtained from nonpregnant and from time-mated rats at 7, 13, 16, 19, and 21 d of pregnancy. Placental tissue was obtained on d 13, 16, 19 and 21 of pregnancy. Tissues were evaluated for HO activity, HO-1, HO-2, leptin and vascular endothelial growth factor protein, and HO-1 and HO-2 mRNA. HO activity in both the uterus and placenta peaked on d 21 of pregnancy. In the uterus, HO-1 and HO-2 protein and total mRNA levels peaked on d 16 of pregnancy, whereas, in the placenta, HO-1 and HO-2 protein levels peaked on d 19. Additionally, placental HO-1 mRNA peaked on d 16, but placental HO-2 mRNA declined toward the end of pregnancy. Placental leptin and vascular endothelial growth factor protein levels followed a similar pattern to placental HO-1 and peaked on d 16. We conclude that there is a clear uterine and placental gestational pattern of HO expression in the rat. This pattern is comparable to that of vascular endothelial growth factor and leptin.

Animals↗
PubMed2003

Heme oxygenase-2 protects against lipid peroxidation-mediated cell loss and impaired motor recovery after traumatic brain injury.

After traumatic brain injury (TBI), substantial extracellular heme is released from hemoproteins during hemorrhage and cell injury. Heme oxygenase (HO) isozymes are thought to detoxify the pro-oxidant heme to the potent antioxidant, bilirubin. HO-1, the inducible isozyme, is expressed in glial populations after injury and may play a protective role. However, the role of HO-2, the predominant and constitutively expressed isozyme in the brain, remains unclear after TBI. We used a controlled cortical impact injury model to determine the extent and mechanism of damage between HO-2 knock-out (KO) (-/-) and wild-type (WT) (+/+) mice. The specific cellular and temporal expressions of HO-2 and HO-1 were characterized by immunocytochemistry and Western blots. HO-2 was immunolocalized in neurons both before and after TBI, whereas HO-1 was highly upregulated in glia only after TBI. HO activity determined by gas chromatography using brain sonicates from injured HO-2 KO mice was significantly less than that of HO-2 wild types, despite the induction of HO-1 expression after TBI. Cell loss was significantly greater in KO mice in areas including the cortex, the CA3 region of hippocampus, and the lateral dorsal thalamus. Furthermore, motor recovery after injury, as measured by the rotarod assay and an inclined beam-walking task, was compromised in the KO mice. Finally, brain tissue from injured HO-2 KO mice exhibited decreased ability to reduce oxidative stress, as measured with an Fe(2+)/ascorbic acid-mediated carbon monoxide generation assay for lipid peroxidation susceptibility. These findings demonstrate that HO-2 expression protects neurons against TBI by reducing lipid peroxidation via the catabolism of free heme.

Animals↗
PubMed2003

A prospective randomized controlled study of phototherapy using blue and blue-green light-emitting devices, and conventional halogen-quartz phototherapy.

OBJECTIVE: To determine the efficacy of blue versus blue-green phototherapy using new light sources with narrow luminous spectra. The devices made of high-intensity gallium nitride light-emitting diodes (LEDs) were also compared to conventional halogen-quartz bulbs phototherapy. DESIGN: Prospective open randomized study. PARTICIPANTS: A total of 114 jaundiced, but otherwise healthy term infants who met the entry criteria for phototherapy set by the American Academy of Pediatrics' Practice Parameter. MAIN OUTCOME MEASURES: The duration of phototherapy and the rate of decrease in total serum bilirubin (TSB). RESULTS: The mean TSB concentrations at initiation and termination of treatment, as well as the duration of phototherapy and the rate of decrease in TSB, were not statistically different in newborns receiving blue LED, blue-green LED or conventional phototherapy. The average rate of decrease in TSB (slope), after adjustment by a linear regression analysis for confounding factors, was -3.61 micromol/hour (95% confidence limits -5.47, -1.75) in the 25 newborns receiving blue LED phototherapy compared with -2.57 micromol/hour (-4.32, -0.82) in the 22 newborns treated with blue-green LED phototherapy and -3.42 micromol/hour (-5.02, -1.81) in the 57 newborns who received conventional phototherapy. CONCLUSIONS: When using low light irradiance, there was no statistically significant difference in the effectiveness of phototherapy using blue-green LEDs, blue LEDs or conventional halogen-quartz bulbs.

Bilirubin↗
PubMed2003

Effect of parenteral glutamine supplementation on plasma amino acid concentrations in extremely low-birth-weight infants.

BACKGROUND: Glutamine is one of the most abundant amino acids in both plasma and human milk and may be conditionally essential in premature infants. However, glutamine is not provided by standard intravenous amino acid solutions. OBJECTIVE: We assessed the effect of parenteral glutamine supplementation on plasma amino acid concentrations in extremely low-birth-weight infants receiving parenteral nutrition (PN). DESIGN: A total of 141 infants with birth weights of 401-1000 g were randomly assigned to receive a standard intravenous amino acid solution that did not contain glutamine or an isonitrogenous amino acid solution with 20% of the total amino acids as glutamine. Blood samples were obtained just before initiation of study PN and again after the infants had received study PN (mean intake: 2.3 +/- 1.0 g amino acids x kg(-1) x d(-1)) for approximately 10 d. RESULTS: Infants randomly assigned to receive glutamine had mean plasma glutamine concentrations that increased significantly and were approximately 30% higher than those in the control group in response to PN (425 +/- 182 and 332 +/- 148 micromol/L for the glutamine and control groups, respectively). There was no significant difference between the 2 groups in the relative change in plasma glutamate concentration between the baseline and PN samples. In both groups, there were significant decreases in plasma phenylalanine and tyrosine between the baseline and PN samples; the decrease in tyrosine was greater in the group that received glutamine. CONCLUSIONS: In extremely low-birth-weight infants, parenteral glutamine supplementation can increase plasma glutamine concentrations without apparent biochemical risk. Currently available amino acid solutions are likely to be suboptimal in their supply of phenylalanine, tyrosine, or both for these infants.

Amino Acids↗
PubMed2003

Effects of metalloporphyrins on heme oxygenase-1 transcription: correlative cell culture assays guide in vivo imaging.

Heme oxygenase (HO) is the rate-limiting step in the heme degradation pathway and is a potential target for the control, or prevention, of pathologic jaundice in neonates. Metalloporphyrins (Mps), a diverse set of synthetic derivatives of heme, can competitively inhibit the HO enzymes. However, certain Mps are phototoxic and some increase transcription of HO-1, the inducible HO isozyme. Therefore, effective development of this class of compounds as therapeutics for treating pathologic jaundice will require rapid and integrated biological screens to identify the most efficacious and safe Mps. To study the safety of these compounds, we assessed their cytotoxic effects and measured luciferase activity by bioluminescent imaging (BLI) as an index of HO-1 transcription, first in live cell cultures and then in living transgenic reporter mice. A total of 12 Mps were first evaluated in the correlative cell culture assay. Based on results from this study, 2 Mps, zinc protoporphyrin (ZnPP) and zinc bis glycol porphyrin (ZnBG), were selected for further studies in the live animal model. In vitro BLI showed ZnPP to be a strong inducer of HO-1 transcription in comparison to ZnBG, which showed minimal induction. Cytotoxicity studies revealed that ZnPP was phototoxic, whereas ZnBG had no effect on cell viability. In vivo BLI showed that both ZnPP and ZnBG had minimal effects on the levels of HO-1 transcription in the animals. Furthermore, serum enzyme assays indicated that neither caused detectable liver toxicity. These findings, and especially those with ZnBG, support the use of selected Mps as therapies for pathologic jaundice. Coupling the high throughput advantage of cell culture with the capability of imaging for whole-body temporal analyses could accelerate and refine the preclinical phases of drug development. Thus, this study serves as a model for understanding the effects of specific compounds in relation to defined targets using an integrated approach.

Animals↗
PubMed2002

Selection of potential therapeutics based on in vivo spatiotemporal transcription patterns of heme oxygenase-1.

Heme oxygenase (HO), a key catabolic enzyme in the conversion of heme to bilirubin, is an ideal target for reducing bilirubin production and preventing pathological jaundice in newborn infants. Metalloporphyrins (Mps) have been well characterized as competitive inhibitors of HO and have been evaluated as potential chemopreventive agents for neonatal jaundice. However, in addition to reducing HO activity, many Mps have been shown to increase HO-1 transcription, which would likely reduce their potential therapeutic utility. The differential effects of Mps on the transcription of HO-1 were therefore evaluated in living transgenic (Tg) reporter mice. Of the compounds evaluated, we observed that zinc bis-glycol porphyrin (ZnBG), a potent inhibitor of HO enzyme activity, did not alter HO-1 transcription patterns in Tg mice. Whole body images of HO-1 transcription patterns did, however; reveal increases in HO-1 transcription in Tg mice after treatment with other Mps, heme and cadmium chloride (CdCl(2)). Intravenous injections of CdCl(2) resulted in expression patterns that differed in tempo and location from those observed in Tg mice treated with intraperitoneal injections. Spatiotemporal analyses of transcriptional regulation in living animals accelerated the assessment of an adverse effect of Mps by revealing different patterns of HO-1 transcription. Among the known inhibitors of HO enzyme activity that were evaluated in this study, ZnBG did not significantly affect HO-1 transcription and therefore may be well suited for the prevention of neonatal jaundice.

Animals↗
PubMed2002

Changes in pathogens causing early-onset sepsis in very-low-birth-weight infants.

BACKGROUND: It is uncertain whether the rates and causes of early-onset sepsis (that occurring within 72 hours after birth) among very-low-birth-weight infants have changed in recent years, since antibiotics have begun to be used more widely during labor and delivery. METHODS: We studied 5447 very-low-birth-weight infants (those weighing between 401 and 1500 g) born at centers of the Neonatal Research Network of the National Institute of Child Health and Human Development between 1998 and 2000 who had at least one blood culture in the first three days of life and compared them with 7606 very-low-birth-weight infants born at centers in the network between 1991 and 1993. RESULTS: Early-onset sepsis (as confirmed by positive blood cultures) was present in 84 infants in the more recent birth cohort (1.5 percent). As compared with the earlier birth cohort, there was a marked reduction in group B streptococcal sepsis (from 5.9 to 1.7 per 1000 live births of infants weighing 401 to 1500 g, P<0.001) and an increase in Escherichia coli sepsis (from 3.2 to 6.8 per 1000 live births, P=0.004); the overall rate of early-onset sepsis was not significantly changed. Most E. coli isolates from the recent birth cohort (85 percent) were resistant to ampicillin, and mothers of infants with ampicillin-resistant E. coli infections were more likely to have received intrapartum ampicillin than were those with ampicillin-sensitive strains (26 of 28 with sensitivity data vs. 1 of 5, P=0.01). Infants with early-onset sepsis were more likely to die than uninfected infants (37 percent vs. 13 percent, P<0.001), especially if they were infected with gram-negative organisms. CONCLUSIONS: Early-onset sepsis remains an uncommon but potentially lethal problem among very-low-birth-weight infants. The change in pathogens over time from predominantly gram-positive to predominantly gram-negative requires confirmation by ongoing surveillance.

Ampicillin↗
PubMed2002

Ethical considerations in neuroimaging and its impact on decision-making for neonates.

Neuroimaging can now provide information about structure and function. Despite new and improved neuroimaging technologies applicable to the newborn, predictions about later cognition, learning, social and emotional behavior, and neuromuscular capabilities, based on images of a fetus inside or a newborn outside the womb, are fraught with difficulties that go beyond technical ones. The interpretation of neuroimages may be necessary but it is not sufficient for decision-making related to the withholding or withdrawing of medical support for neonates. As the explanatory reach of neuroimaging increases, there will still need to be consideration of ethical issues as they relate to the best interests of the neonate and the neonate's parents, the quality of life of the neonate and non-beneficial treatment. Once this is appreciated, the boundary between the technical and the ethical will be less often disputed.

Brain↗
PubMed2002

Hemolysis and bilirubin conjugation in association with UDP-glucuronosyltransferase 1A1 promoter polymorphism.

Hemolysis may contribute to hyperbilirubinemia in Gilbert's syndrome. The authors examined blood carboxyhemoglobin corrected for inspired CO (COHbc) to index heme catabolism and serum conjugated bilirubin fractions to reflect bilirubin conjugation. Both parameters were related to UDP-glucuronosyltransferase 1A1 (UGT) promoter polymorphism, associated with Gilbert's syndrome, in term male newborns. COHbc was expressed as percentage of total hemoglobin, and total conjugated bilirubin (TCB) value as a percentage of serum total bilirubin (STB), (TCB/STB[%]). A production/conjugation index, COHbc/(TCB/STB[%]), represented bilirubin production divided by conjugation. UGT promoter genotype was designated according to the number of promoter TA insertions in each allele: 6/6, homozygous normal; 6/7, heterozygous; 7/7, homozygous variant. STB and COHbc values were higher in the 7/7 subgroup than the other counterparts (P <.01). The COHbc/(TCB/STB[%]) was higher in the 7/7 than either the 6/6 or 6/7 subsets (1.93 [1.31-2.88] vs. 0.85 [0.51-1.72] and 0.84 [0.53-1.87], respectively; P <.01). In conclusion, 7/7 UGT promoter polymorphism was associated with increased blood COHbc values (unexpected finding) as well as diminished serum total conjugated bilirubin ratios (expected finding). The increased hemolysis may contribute to the pathogenesis of increased STB values seen in Gilbert's syndrome, and exacerbate neonatal hyperbilirubinemia associated with the promoter polymorphism.

Bilirubin↗
PubMed2002

Risk factors for early death among extremely low-birth-weight infants.

OBJECTIVE: The purposes of this study were to compare the clinical characteristics of extremely low birth-weight infants (501-1000 g birth weight) who die early (<12 hours of age) with those of infants who die >12 hours after birth and infants who survive to neonatal intensive care unit discharge and to develop a model of risk for early death. STUDY DESIGN: Perinatal data were prospectively collected on 5986 infants in the 12 participating centers of the National Institute of Child Health and Human Development Neonatal Research Network from March 1993 through December 1997. Maternal and neonatal characteristics of infants who died early were compared with infants who survived and infants who died beyond 12 hours of age. A model for risk for early death was developed by logistic regression analysis, with results expressed as odds ratio with 95% CI. RESULTS: Mothers of infants who died early were more likely to be delivered in an inborn setting and experience labor and were less likely to have hypertension or preeclampsia, to receive antenatal corticosteroids, or to be delivered by cesarean birth than mothers of infants who died >12 hours after birth or infants who survived. Infants who died early were more likely to have lower Apgar scores and lower gestational age/birth weight and were less likely to be intubated at birth and to receive mechanical ventilation and surfactant therapy than infants who died >12 hours after birth or infants who survived. Greater risk for early death versus survival to neonatal intensive care unit discharge was associated with the lack of surfactant administration (odds ratio, 8.6; 95% CI, 6.3-11.9), lack of delivery room intubation (odds ratio, 5.3; 95% CI, 3.5-8.1), lack of antenatal corticosteroid use (odds ratio, 2.3; 95% CI, 1.6-3.2), lower 1-minute Apgar score (odds ratio, 2.0; 95% CI, 1.8-2.2), male sex (odds ratio, 1.7; 95% CI, 1.3-2.3), multiple gestation (odds ratio, 1.7; 95% CI, 1.2-2.5), no tocolytics (odds ratio, 1.7; 95% CI, 1.2-2.3), lower gestational age per week (odds ratio, 1.4; 95% CI, 1.3-1.6), and lower birth weight per 50 g (95% CI, 1.2-1.4). CONCLUSION: Early death (<12 hours of age) among extremely low-birth-weight infants may reflect an assessment of non-viability by obstetricians and neonatologists.

Adrenal Cortex Hormones↗
PubMed2002

Neurodevelopmental outcome of premature infants after antenatal phenobarbital exposure.

OBJECTIVE: We previously demonstrated that antenatal phenobarbital does not decrease the risk of intracranial hemorrhage or early death in premature infants. The objective of the present study was to evaluate the impact of antenatal phenobarbital exposure on the neurodevelopmental outcome of premature infants born to women who were participating in the randomized clinical trial of antenatal phenobarbital exposure. STUDY DESIGN: Infants were evaluated at 18 to 22 months corrected age with a standard neurologic examination and the Bayley scales of infant development measuring the mental developmental index and the psychomotor developmental index. RESULTS: Of the 578 infants <34 weeks of gestational age who were born to women who were enrolled in the primary study, 7 infants died after discharge from the neonatal intensive care unit, and 135 infants were lost to follow-up. Infants who were lost to follow-up had a higher mean birth weight and gestational age and a lower maternal education, but the rates of intracranial hemorrhage were comparable to those infants who were evaluated. Among the infants who were evaluated (n = 436; 76%), the mean birth weight and gestational age, maternal education, and frequency and distribution of intracranial hemorrhage were similar in the antenatal phenobarbital exposed and placebo groups. Eighteen infants (8%) in the antenatal phenobarbital exposed group and 21 infants (11%) in the placebo group had cerebral palsy (P = not significant). There was no difference between the 2 groups in either the median Bayley II mental developmental index (85 in the antenatal phenobarbital and 86 in the placebo group) or the Psychomotor Developmental Index (91 in the antenatal phenobarbital and 91 in the placebo group). Infants with intracranial hemorrhage (23%) had significantly lower mental developmental index and psychomotor developmental index scores than infants with no intracranial hemorrhage, independent of antenatal phenobarbital exposure. In the total cohort of 436 infants, the presence of intracranial hemorrhage or periventricular leukomalacia was associated with lower mental developmental index and psychomotor developmental index scores; the presence of increasing birth weight, maternal education, and a complete course of antenatal steroids was associated with a higher mental developmental index score. CONCLUSION: Antenatal phenobarbital exposure did not favorably or adversely affect the neurodevelopmental outcome of premature infants at 18 to 22 months of age.

Anticonvulsants↗
PubMed2002

Late-onset sepsis in very low birth weight neonates: the experience of the NICHD Neonatal Research Network.

OBJECTIVE: Late-onset sepsis (occurring after 3 days of age) is an important problem in very low birth weight (VLBW) infants. To determine the current incidence of late-onset sepsis, risk factors for disease, and the impact of late-onset sepsis on subsequent hospital course, we evaluated a cohort of 6956 VLBW (401-1500 g) neonates admitted to the clinical centers of the National Institute of Child Health and Human Development Neonatal Research Network over a 2-year period (1998-2000). METHODS: The National Institute of Child Health and Human Development Neonatal Research Network maintains a prospective registry of all VLBW neonates admitted to participating centers within 14 days of birth. Expanded infection surveillance was added in 1998. RESULTS: Of 6215 infants who survived beyond 3 days, 1313 (21%) had 1 or more episodes of blood culture-proven late-onset sepsis. The vast majority of infections (70%) were caused by Gram-positive organisms, with coagulase-negative staphylococci accounting for 48% of infections. Rate of infection was inversely related to birth weight and gestational age. Complications of prematurity associated with an increased rate of late-onset sepsis included patent ductus arteriosus, prolonged ventilation, prolonged intravascular access, bronchopulmonary dysplasia, and necrotizing enterocolitis. Infants who developed late-onset sepsis had a significantly prolonged hospital stay (mean length of stay: 79 vs 60 days). They were significantly more likely to die than those who were uninfected (18% vs 7%), especially if they were infected with Gram-negative organisms (36%) or fungi (32%). CONCLUSIONS: Late-onset sepsis remains an important risk factor for death among VLBW preterm infants and for prolonged hospital stay among VLBW survivors. Strategies to reduce late-onset sepsis and its medical, social, and economic toll need to be addressed urgently.

Anti-Infective Agents↗
PubMed2002

Whole-body hypothermia for neonatal encephalopathy: animal observations as a basis for a randomized, controlled pilot study in term infants.

OBJECTIVE: Modest reduction in brain temperature is a promising therapy to reduce brain damage after neonatal encephalopathy as a result of acute perinatal asphyxia. The efficacy of modest hypothermia may in part be dependent on the stability of the desired brain temperature. The objective of this study was 1) to evaluate in newborn animals a commercially available cooling system (Blanketrol II Hyperthermia-Hypothermia system) to control brain temperature during whole-body hypothermia and 2) to use the results of the animal experiments to perform a pilot study evaluating the feasibility of whole-body hypothermia as a neuroprotective therapy for newborns with encephalopathy at birth. METHODS: In the animal investigation, 3 miniature swine were instrumented and ventilated, and temperature probes were placed in the esophagus and the brain (1 cm and 2 cm beneath the parietal cortical surface and the dura). Body cooling was achieved using the automatic control mode (servo) of the cooling system. In the human investigation, 19 term infants with moderate or severe encephalopathy were randomized to either normothermia (n = 10) or hypothermia (n = 9) within 6 hours of birth. Whole-body hypothermia was achieved using the hyperthermia-hypothermia cooling system with servo control of esophageal temperature to 34.5 degrees C for 72 hours followed by slow rewarming. RESULTS: In the animal investigation, body cooling with the animal lying on a single blanket resulted in rapid cooling of the body within 90 minutes. Repetitive cyclical swings in esophageal temperature of 1.7 +/- 0.2 degrees C (mean +/- standard deviation) around the set point of 33.5 degrees C were reduced to 0.7 +/- 0.2 degrees C when a second, larger blanket was attached and suspended. Esophageal temperature was a good marker of deep brain temperature (esophageal to 2-cm brain difference: 0.1 +/- 0.3 degrees C). In the human investigation, the infants were randomized at 4.1 +/- 1.3 hours (mean +/- standard deviation) after birth. Age at randomization was similar in the 2 groups. Cooling was initiated at an average age of 5.3 hours. Target temperature of 34.5 degrees C was achieved within 30 minutes and remained constant throughout the intervention period. Heart rate decreased to 108 +/- 14 beats per minute (bpm) at 60 minutes and remained between 115 and 130 bpm for the duration of cooling compared with 130 to 145 bpm in the normothermia group. Blood pressure was similar in the 2 groups. No adverse events occurred during 72 hours of cooling. The mortality rate and frequency of persistent pulmonary hypertension, renal failure, hepatic dysfunction, and need for pressor support were similar in both groups. CONCLUSIONS: Animal studies showed that a simple modification of a commercially available cooling system (2 blankets attached, subject lying on 1 and the second hanging freely) results in stable core body and brain temperature when used in the automatic control mode. The pilot study in term infants with encephalopathy using this cooling system demonstrates feasibility of initiating whole-body hypothermia at <6 hours of age to a constant esophageal temperature using servo control and provides no evidence that hypothermia involved greater hazard than benefit.

Animals↗